Prestressed post tension suspension bridge cable anchorage

ABSTRACT

By prestressing a suspension bridge cable anchorage at a bearing plate and tensioning the cable strands at different points on the bearing plate, savings in the mass of concrete or scope of anchor rod in rock is obtained, saving labor and material. The anchorage is adapted to different cable strand configurations and facilitates suspension bridge construction and cable anchorage.

United States Patent 1 1 Hedefine et a1.

1 1 PRESTRESSED POST TENSION SUSPENSION BRIDGE CABLE ANCHORAGE [75]Inventors: Alfred Hedefine, Sparta. N.J.; Louis G. Silano, Seaford. NY.

[73] Assignee: Parson, Brinckerhofi, Quade & Douglas, Inc., New York,NY.

[ 1 Feb. 11, 1975 2.132.269 10/1938 McHugh 14/21 2,914,783 12/1959Hoyden 14/21 3.475.777 11/1969 Robinson 14/21 1548.432 12/1970 Durkee14/21 Primary Examim'rNile C. Byers. Jr. Armrney. Agenl, orFirm-Auslander & Thomas [57] ABSTRACT By prestressing a suspensionbridge cable anchorage at a bearing plate and tensioning the cablestrands at different points on the bearing plate, savings in the mass ofconcrete or scope of anchor rod in rock is obtained, saving labor andmaterial. The anchorage is adapted to different cable strandconfigurations and facilitates suspension bridge construction and cableanchorage.

34 Claims, 18 Drawing Figures PATENTEU FEB] sum 1 or a PATENTEDFEBI 1 maSHEET U 0F 8 mIOE * PATENTEDFEBI 915 SHEET 5 OF 8 r 1 PRESTRESSED POSTTENSION SUSPENSION BRIDGE CABLE ANCHORAGE The present invention relatesto a prestressed post tension suspension bridge cable anchorage.

In the past, many efforts have been made to reduce the cost of bothlabor and material in the construction of suspension bridges withoutsacrificing structural strength.

The main cables of suspension bridges built since the beginning of theindustrial era have been of three types: chains, eyebar and wire. Sincethe late 1920's important suspension bridges have used wire cables,which in turn have been of two types: parallel wire cables and helicalwire strand cables.

From the bridge designers point of view, parallel wire cables aresuperior to cables made of helical wire strands. This is becausestraight, parallel laid wires deliver the full strength and modulus ofelasticity of the steel, whereas strength and modulus are both reducedas a result of the helical placement of wires in conventional strands.Consequently, bridge cables of helical strand construction must havesignificantly greater cross-sectional area than those of parallel wireconstruction.

On the other hand, from the bridge erectors standpoint, strand-typecables are superior to the parallel wire type. Strands are readilyerected and adjusted, with minimum equipment and manpower. But aerialspinning" of individual wires, the standard erection procedure forparallel wire cables, is a long, tedious and complex operation,requiring expensive and complicated equipment. For this reason, helicalstrand cables can be used economically on small to medium-sizesuspension bridges, in spite of the resulting increased quantity ofpermanent material.

Parallel wires, rather than helical wires, could be shop manufacturedand socketed, and properly packaged for shipment, then it would bepossible to construct parallel wire bridge cables using the simpleerection techniques applicable to strand-type cables. A cable made ofshop-built parallel wire strands would combine all of the erectionadvantages of strand-type cables with the superior in-placecharacteristics of parallel wire cables.

Whether the cable was spun, parallel or helical, the cable required ananchorage.

The larger the bridge, the heavier the anchorage mass that was requiredto hold the cable and cable strands securely, and further be able towithstand the stress and strain of the suspension bridge under use andweather conditions.

Anchorages usually were in concrete anchorage foundations, in or out ofthe water, or in bed rock. In either case, the amount of concreterequired for the anchorage foundation in or out of water was dictated bythe load calculated for the suspension bridge or the depth of anchoragefoundation in bed rock was dictated by the same consideration.

According to the present invention, an anchorage foundation of concreteor in bed rock is provided, that enables a suspension bridge cable to beanchored using a minimum requirement of concrete or a minimum depth orlesser depth of anchorage in bed rock, size for size and stress forstress, of comparable bridges constructed in the past with a saving oftime and labor because of ease of construction.

The present invention is at the same time adapted for use with parallelspun cable strands, or helical cable strands, or prefabricated parallelwire or strands.

As an incident to the present invention, some applications of thepresent invention enable faster anchorage of the strands and freeinspectability of the cable anchorage, the bearing plates and thestrands and easy alignment of the strands with a minimum of adjustmentor precalculation.

Anchorages of the past have used frames similar to that of the presentinvention. By so doing, the difficult task of aligning the strand splayto the anchorage was made less difficult and a solid anchorage was madeat a rear bearing plate such as shown in U.S. Pat. No. 3,548,432 toDurkee, U.S. Pat. No. 3,475,777 to Robinson even provided anchor rodsthrough the anchor block which wire tensioned the bearing plate andsomewhat made alignment of the strands and rods easier.

Now according to the present invention alignment is made even simplerand prestressing by post tensioning of the bearing plates may be used tothe point of reducing the amount of concrete necessary to go into theanchorage necessary to support the weight and stress of the suspensionbridge and the strands substantially self aligned to the splay in acompact construction which in itself may save concrete.

Although such novel feature or features believed to be characteristic ofthe invention are pointed out in the claims, the invention and themanner in which it may be carried out may be further understood byreference to the description following and the accompanying drawings.

FIG. I is a typical suspension bridge with cable anchorage in the water.

FIG. 2 is a section of a concrete anchorage in water.

FIG. 3 is a frame of anchor cylinders free of concrete.

FIG. 4 is a partial front elevation of the front bearing plate of FIG.3.

FIG. 4a is a reduced partial elevation of the rear bearing plate of FIG.3.

FIG. 5 is a partial sectional plan view of a bearing plate such asexemplified in FIG. 4 including cylinders and structure.

FIG. 6 is a cut-away view of the front and rear bearing plates, ananchor cylinder and a tensioning rod.

FIG. 7 is a cut-away view behind the bearing plate showing a strand shoeand tension rods.

FIG. 7a is a fitting for FIG. 7 for a prefabricated strand anchorage.

FIG. 8 is a partial front elevation of a bearing plate and beams for aprefabricated strand anchorage and tension rods.

FIG. 8a is a partial elevation of the rear bearing plate of FIG. 8.

FIG. 9 is a detail of a bearing plate beam, the rod and strands shimmed.

FIG. 10 is a partial plan section of a beam with details of tension rodsand attached strands.

FIG. 11 is an isometric cut-away view of a base, connected strands andbearing plate against the concrete anchorage.

FIG. lla is an exploded section view of a socket anchor of FIG. 11.

FIG. llb is a closure ring for the socket anchor of FIGS. 10 and I1.

FIG. 12 is a perspective view of an alternate strand shoe forprefabricated strands such as may be used with the bearing plate of FIG.7.

FIG. 13 is a partial section of a bearing plate and rock anchorage ofthe present invention.

Referring now to the figures in greater detail, where like referencenumbers denote like parts in the various figures. v

The suspension bridge as shown in FIG. 1 is suspended by cable 11anchored in concrete anchorages 12 in the mass of anchor blocks 13.

The strands 46 of the cable 11 are fastened to a hearing plate 15, suchas shown in FIG. 4, at one end of an anchor block 13.

A rear bearing plate 16 is shown reduced and cut away in FIG. 4a, whichis at the other end of the anchor block '13.

The bearing plates 15, 16 are usually part of a frame 17 which supportsthe anchor cylinders 18. As can be seen in FIG. 6 a cylinder 18 ispreferably held to the bearing plates 15, 16 by threading sleeves 19extending from the bearing plates 15, 16.

The enormity of dimension of parts may be hard to conceive from thedrawings.

It is oftentimes necessary to couple the anchor cylinders 18 in order toachieve sufficient length by a coupling sleeve 20 as shown in FIG. 6.

The frame 17 is provided with, among other things, channel irons 21 andcylinder supports 22 to hold the anchor cylinders 18 in proper position.

Rods 42 are set up in the anchor cylinders 18 and ultimately tightenedagainst the bearing plates 15, 16 held by nuts 24, usually with washers25 between the nuts 24 and bearing plates 15, 16, although on occasionshims may be used.

The front bearing plate 15, as seen in FIG, 4 and 5 includes a series ofspaced openings 26 through which the rods 42 may pass as shown in FIG.6. The rear bearing plate 16 includes a counterpart of the openings 26in front bearing plate 15.

The front bearing-plate 15 includes a secondary system of openings 27which have a regular flare tapering to a greater width at the front ofthe front bearing plate 15.

In FIG. 5, washers 28 having rounded concavities 32 are provided behindthe flared openings 27 to receive stud bolts 29 as shown in FIG. 7. InFIG. 7, some concrete 30 is shown, as will be more fully discussedlater.

In FIG. 7 the stud bolts 29 are held by rounded nuts 31 which coincidewith a concavity 32 in the washers 28. The stud bolts 29 extend througha shoe 33 shown in section in FIG. 7. The stud bolts 29 are held to theshoe 33 by nuts 34. In FIG. 5, covers 28a for the washers 28 and nuts 31are shown.

The shoe 33 as shown in FIG. 7 is a section ofa double shoe capable ofholding one strand 46 of cable 11 wire on each side of the bolts 29.Each strand 46 is made up of several wires.

The shoe 33 is similar to the structure used in the construction of spunstrands.

, A cover 28a, as shown in FIG. 7, normally protects the nuts 31 andbolts 29 and round washers 28 from poured concrete 30. The covers 28amay be grouted upon completion of the bridge 10.

In FIG. 7a an alternate construction of strand socket 36 is shown. Theconstruction of the socket 36 is one form of socket useable withprefabricated strands which do not have to be spun. The socket 36 may beused with the bearing plate 15.

As shown in FIG. 8, a bearing plate 40 has a series of openings 41adapted to receive rods 42 which are shown held to the beams 43 by nuts44. The other ends of the rods are held to the rear bearing plate 45 inthe same manner as shown in FIG. 6. The strands 46 are only shown insection in FIGS. 8 and 9.

In FIG. 9 a detail of a beam 43 is shown. Washer plate 47 closes the Uchannels 48 and held by the nuts 44.

The strands 46 pass through the U channels 50 and as can be seen inFIGS. 10 and 11, are locked into the beams 43. The rods 42 pass throughthe beam 43, the washer plate 47 and the bearing plate 40 and arefastened to the front of the beam 43.

The beam 43 as shown in FIGS. 10 and 11 has a heavy forward flange 51, amiddle flange 52, a rear flange 53, all of which may be joined by anintermediate webbing 54. The middle supports 52 are heavy to stand greatstress and include U channels 56 into which the strands 46 with sockets57 are held.

The beam 43 also includes two support walls 58, 59 which brace themiddle flange 52 crossing beam 43 with part of its thickness to bracethe rear flange 53.'A central support wall 60 also braces the middleflange 52.

Thinner cross walls 61 span the beam 43 from the forward flange 51 tothe rear flange 53 and serve as a channel for the rods 42 which passbetween the walls 61 and 58, S9.

The strands 46 may be held by a keeper 62 as shown in FIG. 9.

The rods 42 pass through anchor cylinders 18 which are held to thebearing plate 40 by threaded sleeves 19. While not shown, the anchorcylinders 18 are also held by threaded sleeves 19 at the rear bearingplate 45.

The sockets 57 round ends 63 are preferably rounded as shown cut away inFIG. 10.

Engaging a strand in a beam 43 is easily effected by just placing thestrand 46 and socket 57 through the U channels 50, 56. A split washer 64having half sections 65, 66 is then placed about the rounded end 63 ofthe socket 57 and held in position by a keeper ring 67 as shown in FIGS.11, 11a and 11b. Adjustment of the strands 46 is effected by the use offills 68 and shims 69. The use of fills 68 and shims 69 is illustratedin FIG. 11.

In FIG. 12 a strand shoe 70 is shown. The strand shoe 70 is particularlyadaptable for use with bearing plate 15 of FIG. 4. Stud bolts 29 extendfrom the bearing plate 15 and hold the strand shoe 7 with the nuts 34.

Prefabricated strands 46 with their sockets 72 are engaged in the Uchannels 73 and tightened by use of the nuts 34 to take up any slack.

The cable anchorage 80, as shown in FIG. 13, is an anchorage to the massof bed rock 81. Rods 82 are anchored deep into bed rock 81 mass by meanswell known in the art. The rods pass through the bearing plate 83 whichis grouted with concrete 84 so that the interface between the bearingplate 83 and rock 81 and concrete 84 is smooth.

The rear of the bearing plate 83 is preferably provided with cover 28ato protect the stud bolts 29, washer 28 and round nut 31 so that theycan be properly adjusted.

Thus far, the hardware has been described in its physical detail. Muchof it is old in the art and might not show any significance.

In suspension bridges the old method of spinning cable is not entirelyabandoned even though it is generally slow and the labor is expensive.-

Great savings in labor and money have been made by erecting suspensionbridges by unrolling and setting prefabricated cable strands.

The present invention adds a new dimension to suspension bridge buildingby adapting a new advantage to the construction of the cable anchoragewhether in rock or concrete with old-fashioned spun cable or with thenewer prefabricated cable.

The frame 17 with its anchor cylinder 18 and bearing plates 15, 16 isencased in concrete as can be seen in FIG. 1, where the anchor block 13has hardened to concrete.

After the concrete has fully hardened, the rods 42 are tightened againstthe bearing plates 15, 16 with the nuts 24 bearing on the bearing plates15, 16 and are prestressed to a stress about a third greater than thetension the cable 11 and strands 46 are expected to have to bear.

The strands 46 then are anchored to the front bearing plates 15, 40. 83by various means such as shown in FIGS. 5, 7, 7a, 9,10, 11, 12 and 13.

In the completed suspension bridge 10, usually a smaller amount ofconcrete block 13 is required to form the cable anchorage 12. The posttensioning of the anchor block 13 is effected by tensioning the bearingplates 15, 16 by tightening the nuts 24 on the rods 42 against thebearing plates 15, 16, such as shown in FIGS. 6, 7,10 and 11. When thestrands 46 are in place the resultant stress on the anchor block 13 isthe differential of the normal tension from the cable 11, strands 46 andthe stress of post tensioning, thus relieving the anchor block 13 ofmost of the post tensioning stresses. With the present invention, therods 42 and cylinders 18 may be closely set, saving space and concrete.The strands 46 are quickly and easily mounted. The prestressing by posttensioning of the anchor block 13 is made simple, saving labor and time.

In the past, such as shown in U.S. Pat. No. 3,475,777, some ease ofconstruction was achieved by attaching the strands to a post-tensionedrod, post tensioned to the anchor block. Such expedient and the couplingmeans may have facilitated the building of suspension bridges but it hasthe complications of bore-sight align ment and it overlooked theimportance of pretensioning the concrete block before attaching thestrands 46. All the tensions of each strand of the US. Pat. No.3,475,777 depend directly upon each of the individual, post-tensioningrods 42, 82.

The strands 46 of the present invention are each directly or indirectlyconnected to the front bearing plates 15, 40, 83 or bear upon it in someway as are the rods 42, 82, thus any stress on strands 46 or rod 42, 82bears on the entire bearing plate 15, 40, 83 rather than on any oneparticular rod 42. The massiveness of the bearing plate 15, 40, 83 isbetter able to distribute a particular stress than a particular rod.

The concrete anchorage 12, as shown in FIG. 2 usually has a manhole 90and ladder 91 for access to the bearing plate 16. Inspection andmaintenance is facilitated by this. If the rods 42 are ungrouted as yet,or ungrouted, repair may be facilitated.

In FIG. 3, parts of the frame 17 are shown with the concrete faces 100,101, 102, 103, ultimately to form the concrete block 13 flush with thebearing plates 15, 16. In FIG. 4, the openings 26 in the bearing plate15 are for the rods 42 to protrude through. As seen in FIG. 6, a rod 42is shown in the bearing plates 15, 16 held by washers 25 against thebearing plates 15, I6 and tightened by nuts 24.

Inside the bearing plates l5, 16 are threaded sleeves 19 which areanchor cylinder 18 may be screwed into to join the front and rearbearing plates 15, 16. A coupling sleeve 20 may join parts of the anchorcylinder 18 when it is in more than one piece.

The openings 27 are flared wider toward the front of the bearing plate15.

As can be seen in FIG. 7, a washer 28 with a concavity 32 and a nut 31is inside the bearing plate 15 where stud bolts 29 are held by roundednuts 31. The inside of the bearing plate 15 of the stud bolt 29construction is protected by a cover 28a so that when the concrete block13 is poured, this portion will be free to manipulate.

When the bearing plate 15 is set up; it is preferable to install thestuds 29 and nuts 31 in the washers 28 so that the strands 46 may beattached after the concrete has been poured over the frame 17 and theanchor block 13 has been prestressed.

The alignment and adjustment of the sockets 36 or shoes 33, to getproper splay, is easily done from a flat bearing plate 15 by thelatitude of movement the studs 29 have in the flared openings 27 in thebearing plate 15 which appose the cable 11 and the splay of the strand46.

Socket covers 28a, as shown in FIG. 5, may cover the stud 29, washer 28,but 31 construction. The socket covers 28a may be used whether or notthe open area of the socket cover 28a is grouted when the strands 46 arefully placed and adjusted.

The bearing plate 40 is relatively thin. The support for prestressingand post tensioning is found primarily in the beams 43.

Rods 42 pass through the bearing plate 40 openings 41 through thechannels in the beam 43 passing through a U channel 111 at the bearingplate 40 and U channel 48 at the front of the beam 43.

The prestressing is done by tightening the nuts 44 on the rods 42 in thefront of the beam and nuts (not shown) on the bearing plate 45, orotherwise gripping the rods 42 by means known in the art.

Easy adjustment of tension and slack on the rods 42 and beam 43 is takencare of by tightening the nut 44 down on the washer 47 shown in FIG. 9.

Prefabricated strands 46 with sockets 57 are easily placed through the Uchannels 50, 56 behind the middle flange 52, which is in an intermediateposition in the beam 43, where they can be set so their round bottoms 63fit into the rounded split washers 64, held in place by the keeper ring67 and adjusted fills 68 and shims 69.

The stresses of post tensioning of the rods 42 and tensioning of thestrands 46 are again divided to the beam 43 and the bearing plate 40.

Adjustment of the strands 46 under construction and in final use isfacilitated by the ability of the socket 57 to move in the split washerand orient the strand 46 with room for movement provided by the Uchannels 50 which easily adjust for splay just as the flaring of theopening 27 permits the same type of adjustment.

In FIG. 12, the strand shoe 70 is another fitting useable with thebearing plate 13 of FIG. 7. The bearing plate is prestressed asheretofore discussed. The shoe 70 is held by studs 29 and nuts 34. Thestrands 46 are placed in the U channels 73 held in place by keeperplates 62, adjusted for splay and adjusted for length by tightening thenuts 34 and using shims 69, or by using means disclosed or known in theart.

Where solid bed rock is available for a cable anchorage, the advantagesof the present invention are also available.

As is well known in the art, cable strands may be anchored to bed rock81.

When rock is not solid, a concrete anchorage may be carved out of rockand filled with concrete. In such case, the teachings of the presentinvention may be applied.

Where bed rock 81 is available as shown in FIG. 13, the anchorage is toactual rock as distinguished from concrete. The techniques known in theart provide for drilling suitable holes in the rock 81, then securingrods 82.

According to the present invention, savings in labor and/or material andtime may be achieved in the case of rock formations. It saves excavationand allows anchorage of the rods 82 more easily, often with less rods 82or shorter rods 82, with less grouting in a rock mass capable ofsupporting the particular bridge being built.

As shown in FIG. 13, a rod 82 is secured by means known in the art. Abearing plate 83 rests flat against the jagged surface spaced by grout84 between the rock 81 and plate 83.

A rounded washer 28, stud bolt 29 and round nut 31 allow the stud bolt29 to be attached to a strand fitting. The rod 82 and other rods 82 (notshown) are stressed between the bearing plate 83 and the anchorage ofthe rod 82; the strands are tensioned as stated before, leaving greaterstress on the rods 82.

The stresses are then balanced, with greater stress on the rock anchorand counterbalanced by the cable strand tensioning. Stresses aredistributed throughout the bearing plate 83.

The cover 28a is for access. It may be left open or grouted whenconstruction is complete.

Overall, when prestressing and post tensioning in concrete, according tothe present invention, there is a good saving of concrete required toanchor the cable and a concommitant material cost and saving of laborbecause the anchorage 13 is constructable is a very compact space.

According to the present invention, the compactness of the anchorage l2usually obviates the use of more concrete than is necessary to supportthe weight of the bridge 10 with a concommitant saving of labor.

By the same token, according to, the present invention,.when anchoringin bed rock 81, the savings comes in the rock excavation and materialand labor, because of the simplicity of installation.

Whenever used herein, the phrase U-shaped channel refers to a slot,whether of parallel sides of angulated sides, shaped to receive itsselected rod or strand. The bottom portion of said U-shaped channel doesnot necessarily have to be round.

Unless otherwise specified, specific shapes are not of the essence,where round, square or other shapes serve the same functional purposes.

The terms and expression which are employed are used as terms ofdescription; it is recognized, though, that various modifications arepossible.

Having thus described certain forms of the invention in some detail,what is claimed is:

1. In a suspension bridge a cable anchorage construction comprising ananchorage mass, a cable, said cable including at least one cable strand,a bearing plate apposed to said cable, at least one rod opening in saidbearing plate, at least one rod, said at least one rod gripped at leastat one of its ends remote from said bearing plate, the other end of saidat least one rod extending through at least one bearing plate opening,means to fasten said at least one extending rod held bearing upon saidbearing plate, means bearing upon said bearing plate to hold said atleast one said cable strand, tightening means including said bearingplate and said at least one rod to stress said cable anchor mass, meansclear of said at least one rod held bearing upon said bearing plate toretain at least one cable strand, and means to tension said at least onecable strand against said anchorage masss stress.

2. The invention of claim I wherein said anchorage mass is bedrock.

3. The invention of claim 2 wherein said at least one rod is heldfastened in said bedrock.

4. The invention of claim 3 wherein said bedrock is stressed bytightening said at least one rod against said bearing plate.

5. The invention of claim 4 wherein said means to hold said cable strandincludes means to orient said holding means to the splay of said atleast one cable strand.

6. The invention of claim 5 wherein said means to hold said cable strandincludes a protective cover.

7. The invention of claim 1 wherein said anchorage mass is substantiallyconcrete.

8. The invention of claim 7 including a frame, a front bearing plate, arear bearing plate, at least one anchor cylinder and at least one heldrod bearing upon said front and rear bearing plate.

9. The invention of claim 8 wherein said front and rear bearing platesinclude at least one sleeve, said at least one anchor cylinder held bysaid sleeve.

10. The invention of claim 9 wherein said sleeve and at least one anchorcylinder are threaded.

11. The invention of claim 10 wherein said rear bearing plate includesat least one opening for at least one rod, said front bearing plateincludes at least one opening for at least one rod and at least anotheropening for means to hold at least one cable strand.

12. The invention of claim 11 wherein said concrete mass is stressed bytightening said at least one rod against said concrete mass between saidfront and rear bearing plates.

13. The invention of claim 12 wherein said at least one cable strand isspun on a shoe, said shoe held to said front bearing plate by at leastone stud bolt.

14. The invention of claim 13 wherein said at least one stud bolt isheld to said front bearing plate by a rounded bottom nut.

15. The invention of claim 14 wherein said nut rests in a roundedwasher.

16. The invention of claim wherein said opening in said bearing platefor said cable strand holding means is flared outward to the face ofsaid front bearing plate.

17. The invention of claim 12 wherein said at least one cable isprefabricated and includes a socket.

18. The invention of claim 17 wherein said socket is held by at leastone stud bolt.

19. The invention of claim 18 wherein said at least one stud bolt isheld to said front bearing plate by a rounded bottom nut.

20. The invention of claim 19 wherein said nut rests in a roundedwasher.

21. The invention of claim 20 wherein said opening in said bearing platefor said cable strand holding means is flared outward to the face ofsaid front bearing plate.

22. The invention of claim 17 wherein said socket is T shaped.

23. The invention of claim 17 including a shoe having at least oneU-shaped channel wider than said strand and having a socket wider thansaid U-shaped channel.

24. The invention of claim 8 wherein said bearing plate includes atleast one beam adapted to interact with said bearing plate.

25. The invention of claim 24 wherein said beam includes a front flangeand a rear flange and support means, at least one U channel in its frontand rear flanges adapted to receive at least one rod at said frontflange, means to hold said at least one rod on said front flange, atleast one intermediate flange having a U channel apposed to a U channelin said front flange, and at least one cable strand narrower than said Uchannel with a socket wider than said U channel.

26. The invention of claim 25 wherein said means to hold said at leastone rod includes at least one fill.

27. The invention of claim 26 further including at least one shim.

28. The invention of claim 27 wherein said at least one shim includes aU channel.

29. The invention of claim 28 wherein said at least one cable strand isprefabricated.

30. The invention of claim 29 wherein said cable strand includes atleast one socket having a rounded portion facing the length of saidstrand.

31. The invention of claim 29 wherein said at least one socket ismounted in a rounded washer.

32. The invention of claim 31 wherein said rounded washer is split intomore than one piece and adapted to be held together by a keeper.

33. The invention of claim 23 wherein said socket mounting includes atleast one fill.

34. The invention of claim 33 further including at least one shim.

1. In a suspension bridge a cable anchorage construction comprising ananchorage mass, a cable, said cable including at least one cable strand,a bearing plate apposed to said cable, at least one rod opening in saidbearing plate, at least one rod, said at least one rod gripped at leastat one of its ends remote from said bearing plate, the other end of saidat least one rod extending through at least one bearing plate opening,means to fasten said at least one extending rod held bearing upon saidbearing plate, means bearing upon said bearing plate to hold said atleast one said cable strand, tightening means including said bearingplate and said at least one rod to stress said cable anchor mass, meansclear of said at least one rod held bearing upon said bearing plate toretain at least one cable strand, and means to tension said at least onecable strand against said anchorage mass''s stress.
 2. The invention ofclaim 1 wherein said anchorage mass is bedrock.
 3. The invention ofclaim 2 wherein said at least one rod is held fastened in said bedrock.4. The invention of claim 3 wherein said bedrock is stressed bytightening said at least one rod against said bearing plate.
 5. Theinvention of claim 4 wherein said means to hold said cable strandincludes means to orient said holding means to the splay of said atleast one cable strand.
 6. The invention of claim 5 wherein said meansto hold said cable strand includes a protective cover.
 7. The inventionof claim 1 wherein said anchorage mass is substantially concrete.
 8. Theinvention of claim 7 including a frame, a front bearing plate, a rearbearing plate, at least one anchor cylinder and at least one held rodbearing upon said front and rear bearing plate.
 9. The invention ofclaim 8 wherein said front and rear bearing plates include at least onesleeve, said at least one anchor cylinder held by said sleeve.
 10. Theinvention of claim 9 wherein said sleeve and at least one anchorcylinder are threaded.
 11. The invention of claim 10 wherein said rearbearing plate includes at least one opening for at least one rod, saidfront bearing plate includes at least one opening for at least one rodand at least another opening for means to hold at least one cablestrand.
 12. The invention of claim 11 wherein said concrete mass isstressed by tightening said at least one rod against said concrete massbetween said front and rear bearing plates.
 13. The invention of claim12 wherein said at least one cable strand is spun on a shoe, said shoeheld to said front bearing plate by at least one stud bolt.
 14. Theinvention of claim 13 wherein said at least one stud bolt is held tosaid front bearing plate by a rounded bottom nut.
 15. The invention ofclaim 14 wherein said nut rests in a rounded washer.
 16. The inventionof claim 15 wherein said opening in said bearing plate for said cablestrand holding means is flared outward to the face of said front bearingplate.
 17. The invention of claim 12 wherein said at least one cable isprefabricated and includes a socket.
 18. The invention of claim 17wherein said socket is held by at least one stud bolt.
 19. The inventionof claim 18 wherein said at least one stud bolt is held to said frontbearing plate by a rounded bottom nut.
 20. The invention of claim 19wherein said nut rests in a rounded washer.
 21. The invention of claim20 wherein said opening in said bearing plate for said cable strandholding means is flared outward to the face of said front bearing plate.22. The invention of claim 17 wherein said socket is T shaped.
 23. Theinvention of claim 17 including a shoe having at least one U-shapedchannel wider than said strand and having a socket wider than saidU-shaped channel.
 24. The invention of claim 8 wherein said bearingplate includes at least one beam adapted to interact with said bearingplate.
 25. The invention of claim 24 wherein said beam includes a frontflange and a rear flange And support means, at least one U channel inits front and rear flanges adapted to receive at least one rod at saidfront flange, means to hold said at least one rod on said front flange,at least one intermediate flange having a U channel apposed to a Uchannel in said front flange, and at least one cable strand narrowerthan said U channel with a socket wider than said U channel.
 26. Theinvention of claim 25 wherein said means to hold said at least one rodincludes at least one fill.
 27. The invention of claim 26 furtherincluding at least one shim.
 28. The invention of claim 27 wherein saidat least one shim includes a U channel.
 29. The invention of claim 28wherein said at least one cable strand is prefabricated.
 30. Theinvention of claim 29 wherein said cable strand includes at least onesocket having a rounded portion facing the length of said strand. 31.The invention of claim 29 wherein said at least one socket is mounted ina rounded washer.
 32. The invention of claim 31 wherein said roundedwasher is split into more than one piece and adapted to be held togetherby a keeper.
 33. The invention of claim 23 wherein said socket mountingincludes at least one fill.
 34. The invention of claim 33 furtherincluding at least one shim.